From: sashiko-bot@kernel.org
To: "Jacob Lefkowitz" <jlefkowi@akamai.com>
Cc: linux-perf-users@vger.kernel.org
Subject: Re: [PATCH v2 1/2] perf jevents: add iommu page table walk metrics
Date: Mon, 02 Nov 2026 21:22:14 +0000 [thread overview]
Message-ID: <sashiko-outbox-194191@kernel.org> (raw)
In-Reply-To: <20261102-perf-tools-next-v2-1-4d237f886710@akamai.com>
> From: Jacob Lefkowitz <jlefkowi@akamai.com>
>
> Adds page table walk metrics specfically to perf jevents for AMD
> platforms to enhance observability into IOMMU overhead. The metrics
> are supported on Zen 2 and neweer processors. They are implemented
> using the amd_iommu PMU events.
>
> The list of metrics added here are:
> - lpm_iommu_ptw_reads_per_tlb_miss
> - lpm_iommu_ptw_nested_read_ratio
> - lpm_iommu_ptw_guest_read_ratio
> - lpm_iommu_trans_per_sec
>
> The changes here have been tested with 'sleep 10' as the workload:
>
> perf stat -M iommuptw --per-socket --metric-only -j -a -- sleep 10
> {"socket" : "S0", "counters" : 8,
> "reads/tlb_miss lpm_iommu_ptw_reads_per_tlb_miss" : "0.5",
> "% lpm_iommu_ptw_nested_read_ratio" : "none",
> "% lpm_iommu_ptw_guest_read_ratio" : "0.0",
> "trans/s lpm_iommu_trans_per_sec" : "971.5"}
> {"socket" : "S1", "counters" : 0,
> "reads/tlb_miss lpm_iommu_ptw_reads_per_tlb_miss" : "none",
> "% lpm_iommu_ptw_nested_read_ratio" : "none",
> "% lpm_iommu_ptw_guest_read_ratio" : "none,
> "trans/s lpm_iommu_trans_per_sec" : "none"}
>
> Signed-off-by: Jacob Lefkowitz <jlefkowi@akamai.com>
Sashiko has reviewed this patch and found no issues.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261102-perf-tools-next-v2-0-4d237f886710@akamai.com?part=1
next prev parent reply other threads:[~2026-11-02 21:22 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-02 21:14 [PATCH v2 0/2] perf jevents: Add IOMMU PTW & device entry metrics Jacob Lefkowitz via B4 Relay
2026-11-02 21:14 ` [PATCH v2 1/2] perf jevents: add iommu page table walk metrics Jacob Lefkowitz via B4 Relay
2026-11-02 21:22 ` sashiko-bot [this message]
2026-11-02 21:14 ` [PATCH v2 2/2] perf jevents: add amd specific device table entry metrics Jacob Lefkowitz via B4 Relay
2026-11-02 21:18 ` sashiko-bot
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